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Vaccines/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Moby stands next to a bathroom door. A toilet flushes, and Tim comes out. He is wiping his hands with a packaged soapy towel. MOBY: Beep? Moby stares at Tim. TIM: Germs. Moby hands Tim an envelope. Tim opens it and reads from a typed letter. TIM: Dear Tim and Moby, How do vaccines work? From, Gregor. Hi, Gregor! Vaccines trick your body into thinking it's been infected by a particular germ. An animation shows a syringe injecting a vaccine into someone's arm. TIM: Your immune system responds as though it's fighting an organism that could make you sick. Images show a vaccine and a germ. The vaccine is represented by green triangles. The germ is yellow, with similar green triangles all over it. TIM: You build up an immunity to the illness you're being vaccinated for, even though you've never actually had it. So if you ever do get infected with that germ, your body will be ready to fight back. An animation shows a "no" symbol over a germ. MOBY: Beep. TIM: Right. It's sort of like a training session for your body's defenses. In order to get exactly how vaccines work, you need to know a little bit about the immune system. The immune system is responsible for fighting illness and disease. An animation shows different types of white blood cells. Those labeled "T" wea sunglasses and headsets with microphones. Those labeled "B" have test tubes and magnifying glasses. Other white blood cells have fangs. TIM: Every day, bacteria and viruses invade your body. An animation shows different sorts of bacteria and viruses in the air. Tim inhales, and several of them enter his body through his mouth. TIM: In most cases, these germs are stopped or killed by your body's first defenses, like the mucus in your nose, which traps organisms. An animation shows organisms being trapped on hairs covered in mucus. Tim sneezes, and many of the organisms inside him are blown back into the surrounding air. TIM: Sometimes germs get past those defenses and make it into your bloodstream. An animation shows a germ in a human bloodstream. TIM: White blood cells, or leukocytes, patrol your bloodstream looking for harmful invaders. If the leukocytes recognize a bad germ, they'll kill it before you get sick. An animation shows a white blood cell, wearing sunglasses and a headset, in a human bloodstream. It locates a germ and radios to another white blood cell, which eats the germ. TIM: But if, for some reason, they fail to notice a bad germ, it can multiply, invade your cells, and make you sick. An animation shows an unnoticed germ. It divides into two. Then each of the two new germs divides into two more, and so on. MOBY: Beep. TIM: No, no—well, that's when white blood cells create antibodies to fight the infection. An antibody is a protein that binds with a specific molecule, or antigen, found only on the invading germ. An animation shows a white blood cell, labeled with a "T," encountering the germs and radioing to another white blood cell, labeled with a "B." That white blood cell releases a number of antibodies from a test tube. They cling to the antigens, represented as green triangles, on the germs. TIM: The antibody is like a red flag—it signals leukocytes to kill the germ. A group of leukocytes appears and starts eating the germs. TIM: Some antibodies can also neutralize germs on their own. A group of antibodies attach themselves to a germ's antigens until the germ disappears. TIM: After your immune system has stopped the infection, memory cells patrol your blood. They keep watch for that one specific antigen, usually for the rest of your life! Memory cells, labeled with either the letter B or T, float through the bloodstream, with magnifying glasses. MOBY: Beep! TIM: Yep. That's why kids who get chicken pox almost never get it again. Their memory cells recognize the virus quickly the next time it shows up. An animation shows a young girl with chicken pox all over her face. TIM: This is called natural immunity. It happens as a result of your body successfully fighting off an illness. The chicken pox spots disappear from the girl's face, and she smiles. TIM: Vaccines give you immunity without the risks and discomfort of getting sick. They're composed of the antigens from a specific germ. Which are introduced into your body to trigger an immune response. An animation shows an syringe filled with triangular antigens. It is injected under the skin. TIM: Your white blood cells react to those invaders as they normally would. They recognize the antigens and create antibodies for them. An animation shows a white blood cell encountering the antigens and radioing to another white blood cell. That white blood cell produces a number of antibodies from a test tube, which cling to the antigens. The antigens are attacked by the antibodies and eaten by the white blood cells. Then memory cells float through the blood stream keeping watch for that antigen. MOBY: Beep? TIM: Well, vaccines only contain altered or weakened forms of the germs, or none at all. That's why they don't make you sick. An image shows a doctor holding a syringe. A smiling boy sits on a table with a small bandage on his arm. TIM: That's why many vaccinations need several doses to work; since there's not enough of the germ to make you sick, your body's immune response may be very limited. Images show the same boy getting vaccinated at different points in time. MOBY: Beep? TIM: Well, no one likes needles, but they're better than getting sick! And vaccines don't just protect individuals—they protect the whole population. When enough people in an area are vaccinated, they achieve something called herd immunity. That means a specific germ can't find anyone to infect. An animation shows a group of smiling blue figures, connected to one another by dotted lines. One faceless yellow figure stands in the middle. A germ bumps around the blue figures until it raises a white flag. TIM: Herd immunity protects people who can't be vaccinated because their bodies are very sensitive. Like, babies and cancer patients. The yellow figure in the middle of the blue figures smiles. TIM: If we don't maintain our herd immunity, diseases can come back. Some places with low vaccination rates have already had measles outbreaks. Some of the blue figures turn yellow. The germ bounces among them as they turn red and frown. TIM: Unless you live on one of those places, you've probably never met a young person who's had the measles. Or polio, or smallpox. Images show people infected with each of the diseases Tim names. A boy with smallpox has red spots all over his face, a girl with polio is in a wheelchair, and a girl with measles is covered in red blotches. TIM: That's because vaccines have stopped these diseases from spreading. MOBY: Beep? TIM: Doctors are still working on vaccines for many viruses, like HIV, the virus that leads to AIDS. An image shows the HIV virus. TIM: And every year, a new flu vaccine has to be prepared. That's because the flu virus is constantly changing. An animation shows a flu germ changing appearance. The scene changes to show Moby looking concerned and wiping his hands with a soapy towel. TIM: I don't think you need those. MOBY: Beep. TIM: After all, they don't work against computer viruses. Tim grins while Moby frowns. Category:BrainPOP Transcripts